Dynamics and morpho-sedimentary interactions in the lower mesotidal estuary of Villaviciosa (NW Spain): A management proposal

Abstract

The accumulation of sediment in the mouth of Villaviciosa estuary (NW Spain) is becoming an obstacle for the safe navigation in this estuary. One sector of its outer inlet is characterised by a broad shoal linked with a longshore bar of a beach, whose erosion is causing the silting of this area. On this basis, this paper aims to describe the processes that occurred in the lower part of the estuary due to the anthropogenic activities in the channel and inlet. For this purpose, several measurements were made in the water column and in the sedimentary bottoms to characterise the processes that occur in this area. Based on these results, a dynamic and morpho-sedimentary model was developed to examine the interactions between the lower estuary and the exposed part of the confining barrier beach, which allows to establish the evolutionary trends of sedimentary bottoms linked to the marina of El Puntal. Different management measures are carried out to reduce the impact of the sediment accumulation on the navigability, such as periodically dredging in the inlet of the estuary, and the subsequent dumping of the sediments in areas near to the closure depth. Consequently, future retreat of narrow inlet and sandy shoal can be avoided, maintaining the sedimentary volume in the system.